Skin rash caused by dermatitis, often referred to as diaper rash, has always been a problem encountered by the users of disposable absorbent articles, such as diapers, incontinence articles, sanitary towels, training pants etc. Therefore, one of the biggest needs for these users is a solution to this type of skin rash problem.
The main factor which influences the development of skin rash is the contact of the skin with the wet body exudates, directly or for example contained in the absorbent article. Especially when the water content is high, skin rash can occur easily.
Manufacturers of diapers and skin care products have developed various products over the past decades which help reduce the occurrence of diaper rash (or skin rash).
The main focus thereby has been to reduce the exposure of the skin to the body exudates. This is for example done by introduction to the diaper of absorbing or better absorbing materials. The amount of water which is in contact with the skin is thus reduced.
Other products which are developed to address the skin-rash problem reduce the exposure of the skin to certain ingredients of the body exudates. An example of such ingredients of the exudate are bacteria which can infect the skin and thus start off or aggravate the skin rash.
For example, lotions have been developed which can form a barrier between the skin and the body exudates. Also, anti-inflammatory compositions can be applied to the skin or absorbent article.
EP 0191128 discloses a preparation comprising 8-hydroxy quinoline sulphate for treatment of skin irritation.
However, still one of the most heard complaints amongst users of absorbent articles such as diapers is the persistence of skin or diaper rash, despite the numerous products on the market which can be applied to prevent diaper or skin rash.
It has been discovered that yet another factor can set off or aggravate skin rash, namely the presence in the body exudate of various enzymes, especially lipase and protease enzymes.
EP 0117632B relates to disposable articles which comprise lipase inhibiting agents, preferably zinc containing components, and a vehicle material. Also mentioned is the use of glyceryl triacetate
When the skin is exposed to lipase enzymes, the lipids of the skin can be affected by these enzymes. Furthermore, the protease enzymes present in the body exudate on the skin can affect the proteins (or peptides) of the skin. The protection or barrier function of the top layer of the skin (the Strateum Corneum) will thus be diminished. This can effect the health of the skin and/or facilitate the infection of the skin. This can thus lead to skin or diaper rash.
It has been found that triester compounds similar to lipids or the lipids of the skin in particular can function as enzyme substrates, which, when acted upon by a hydrolysing esterase enzyme, such as lipase enzymes, will be hydrolysed resulting in the release of free acids. Firstly, the presence of these acids will lower the pH of the area where the esters where topical applied to. This will amount to inactivation of all or most enzymes present in this area, in the body exudates, such as the lipase enzymes, protease enzymes. Secondly, the esterase or lipase enzymes are ‘de-activated’, because rather than hydrolysing the esters, such as lipids, of the skin, they hydrolyse the alternative substrate, the triester compounds of the invention.
It is known that bile salts are present in the body exudates. These bile salts are known to emulsify the lipase enzymes in the body, which ensures that the lipase enzymes are capable of performing on the lipid-water interface. It has been found that these bile salts still have an emulsifying function once outside the body, in the body exudates. They aid the lipase enzyme which is present in the body exudate by attacking the lipids in the outer layer skin, exposed to the body exudate.
The inventors have found that these bile salts can be inactivated (and thereby the lipase can be deactivated) when the bile salts are reacted with specific cationic compounds. They have found that the compositions comprising the cationic compounds can thereto be applied directly to the skin. This can be done by introduction of the composition into a cosmetic cream, lotion, oil, powder. Alternatively, the composition can be applied to an absorbent article, such as a diaper, which then can be applied to the skin.
Surprisingly it has been found that the use of a combination of the cationic compounds and the triester compounds has an enhanced and elongated effect on the skin-rash or lipolytic dermatitis. Unexpectingly, it has been found that the inhibition or inactivation of the lipase enzymes by the inactivation of the bile salts by the cationic compounds does not make the triester compounds less useful as enzyme substrates. Namely, it has been found that the cationic compounds provide an immediate effect, i.e. inhibition or inactivation of the lipase enzymes, which may reduce over time, whilst the effect of the triester compounds is relatively delayed but long-lasting. Thus, the combination of the two compounds provides an very effective, immediate and long-lasting reduction or prevention of the diaper/skin rash, resulting from dermatitis caused by the enzymes present on the body exudates on the skin.